I agree, I've added caching to my local patched version a while ago. Is buggy though (doesn't properly detect incomplete downloads) so I'm reluctant to share it. 

What about testzip to see if the archive is good. Also do the revisions have hashes or anything that can be checked

https://docs.python.org/3/library/zipfile.html#zipfile.ZipFile.testzip

Ah, there was a typo in my code (my python skillz are almost 0).
I'm attaching the mod which you'll have to edit to change the folder(s) for downloaded builds cache and 7zip exe path

* 7zip is required because my mod downloads much smaller mini_installer.exe (40MB)
* the output is colorized so it requires "colorama" module for python and an alternative console wrapper like ConEmu in Windows
* the downloaded revisions are automatically saved in the specified cache folder named like 515313.7z or 507287x64.7z
* -a win32 is selected by default but both x64 and standard 7z are used from cache folder because it doesn't matter usually;
  you can run with -a win64 so the script will use x64 builds from the cache
* no need to press the Enter key when answering good/bad question

Anyway, it's up to you to edit/customize it.

Deleted: bisect-builds2.py 49.4 KB

bisect-builds2.py 49.4 KB View Download

issue seems to be related to bisect script and doesn't look directly related to chrome. Hence adding 'TE-NeedsTriageHelp' label to move this out of TE Unconfirmed issues triaging bucket.

Requesting someone from the respective team to have a look at this request.

woxxom, thanks for sharing your changes. I made a few modifications to get it working for me and put it up at https://github.com/jay/chrome-bisect-builds in branch woxxom

This sounds unrelated to the automated bisect system, so removing the Speed>Bisection component.